Gas turbine combustor and method of operating the same

Abstract

The gas turbine combustor and the operation method thereof are designed to minimize visualization of exhaust gas from the gas turbine upon switching of the gas turbine fuel from the oil fuel to the gas fuel. Upon switching of the combustion by the pilot burner from the oil burning to the gas burning, the gas fuel is supplied to the main burners so as to start the gas burning. Then the gas fuel is supplied to the pilot burner to start the gas burning.

What is claimed is: 
     
       1. A method of operating a gas turbine combustor which includes a pilot burner and a main burner arranged around an outer circumference of the pilot burner, the pilot burner being configured to be capable of performing an oil burning operation and a gas burning operation, and the main burner being configured to be capable of performing at least the gas burning operation,
 wherein upon switching of a combustion by the pilot burner from the oil burning operation to the gas burning operation, a gas fuel is supplied to the main burner to start the gas burning operation, and subsequent to starting the gas burning operation in the main burner the gas fuel is supplied to the pilot burner to start the gas burning operation in the pilot burner. 
 
     
     
       2. The method of operating a gas turbine combustor according to  claim 1 ,
 wherein in a process of the gas burning operation in which the gas fuel is supplied to the main burner to perform the gas burning operation, inert gas is supplied to a gas burner of the pilot burner. 
 
     
     
       3. A gas turbine combustor which includes a pilot burner and a main burner arranged around an outer circumference of the pilot burner, the pilot burner being configured to be capable of performing an oil burning operation and a gas burning operation, and the main burner being configured to be capable of performing at least the gas burning operation, the gas turbine combustor comprising:
 an oil fuel supply system configured to supply an oil fuel to an oil fuel nozzle of the pilot burner and provided with an oil fuel flow control valve; 
 a pilot burner gas fuel supply system configured to supply a gas fuel to a gas fuel nozzle of the pilot burner and provided with a pilot burner gas fuel flow control valve; 
 a main burner gas fuel supply system configured to supply the gas fuel to a gas fuel nozzle of the main burner and provided with a main burner gas fuel flow control valve; and 
 a control device which is configured to send out a control instruction for controlling each opening degree of the oil fuel flow control valve, the pilot burner gas fuel flow control valve, and the main burner gas fuel flow control valve, 
 wherein upon switching of a combustion by the pilot burner from the oil burning operation to the gas burning operation, the control device is configured to send out instructions to gradually close the oil fuel flow control valve by reducing the opening degree and to gradually open the main burner gas fuel flow control valve by increasing the opening degree, and is configured to, subsequent to sending out the instructions to the oil fuel flow control valve and the main burner gas fuel flow control valve, send out instructions to gradually open the pilot burner gas fuel flow control valve while keeping the main burner gas fuel flow control valve opened, and to fully close the oil fuel flow control valve. 
 
     
     
       4. The gas turbine combustor according to  claim 3 , further comprising an inert gas supply system configured to supply inert gas to the gas fuel nozzle of the pilot burner and provided with an inert gas flow control valve,
 wherein the control device is further configured to send out an instruction to open the inert gas flow control valve at a timing before opening of the pilot burner gas fuel flow control valve subsequent to generation of a flame by the main burner through opening of the main burner gas fuel flow control valve.